Some loudspeaker suspension materials exhibit significant creep (continued slow displacement under sustained force) in their dynamic behavior. In this study the traditional low-frequency loudspeaker model is expanded to incorporate suspension creep by replacing the simple linear compliance with a dynamic transfer function. Three creep models are developed, partly from viscoelastic theory, partly from empirical considerations. Experiments on three different woofers demonstrate that the expanded models are able to fit the measured frequency- and time-domain data much better than the traditional model. The expanded model structures are further supported by the results from cross-validation experients. Since an inappropriate model structure may be the cause of systematic errors in estimated parameter values, a salient merit of the expanded models is improved accuracy in loudspeaker parameter experiments.
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